1. Field of the Invention
This invention relates to a novel neurotransmitter Neuropeptide Y receptor, its nucleic acid sequence, and compounds, compositions, and methods for their use.
2. Summary of the Related Art
Neuropeptide Y (NPY) is a 36-amino acid peptide neurotransmitter that is located throughout the central and peripheral nervous systems. Tatemoto, Proc. Natl. Acad Sci. USA 79, 5485 (1982); Hazlewood, Proc. Soc. Exp. Biol. Med. 202, 44 (1993). It affects a broad range of phenomena, including blood pressure regulation, memory, anxiolysis/sedation, food and water appetite, vascular and other smooth muscle activity, intestinal electrolyte secretion, and urinary sodium excretion. E.g., Colmers and Wahlestedt, The Biology of Neuropeptide Y and Related Peptides (Humana Press, Totowa, N.J., 1993); Kalra et al., Phys. and Behavior 50, 5 (1991).
Peptide YY (PYY) is also a 36 amino acid peptide and has significant sequence homology (70%) to NPY. Tatemoto et al., Nature 296, 659 (1982). Its anatomical distribution is similar to that of NPY, although it is located mainly in the endocrine cells of the lower gastrointestinal tract. Bottcher et al., Regul. Pept. 8, 261 (1984). Like NPY, PYY stimulates feeding in rats. Morley et al., Brain Res. 341, 200 (1985). Along with the pancreatic polypeptide (PP), NPY and PYY have a common tertiary structure, characterized by the so-called PP-fold. Glover, Eur. J. Biochem. 142, 379 (1985). Both NPY and PYY show about a 50% sequence homology with PP.
Because of their structural similarities, NPY and PYY have a number of common receptors. At least four receptor subtypes, Y1, Y2, Y3, and Y4/PP, have been identified. The affinity for NPY, PYY, and various fragments thereof varies among the subtypes. See, e.g., Bard et al. (WO 95/17906) and references cited therein. For example, Y1 and Y2 subtypes have high affinity for NPY and PYY. Whereas Y1 has high affinity for (Leu31Pro34)NPY ((LP)NPY) and low affinity for (13-36)NPY, Y2 behaves oppositely. Y3 has high affinity for NPY but low affinity for PYY. Y4/PP has a high affinity for PP but relatively low affinity for NPY.
Wahlestedt (WO 93/24515) and Larhammar et al. (J Biol. Chem. 267, 10935 (1992)) describe the cloning and identification of the human Y1-type NPY/PYY receptor isolated from human fetal brain tissue. Selbie et al. (WO 93/09227) disclosed the full length cDNA sequence of the Y1 receptor from human hippocampus. Eva et al. (FEBS Lett. 271, 81 (1990)) cloned the NPY Y1 receptor from rat forebrain. Eva et al. (FEBS Lett. 314, 285 (1992)) cloned the NPY Y1 receptor from murine genomic DNA.
The Y2-type receptor has also been cloned. Gerald et al. (WO 95/21245) disclosed the cDNA sequence of human hippocampal Y2 and two rat Y2 clones. Rose et al. (J. Biol. Chem. 270, 22661 (1995)) disclosed the cDNA sequence of the Y2 receptor from a human neuroblastoma cell line.
Bard et al. (supra) and Lundell et al. (J. Biol. Chem. 270, 29123 (1995)) described cloning the cDNA sequence of the Y4/PP receptor from both rat spleen and human placenta.
To date, the Y3 receptor has not been cloned.
Because of the important role of NPY and PYY in a number of physiological processes., such as feeding, there is a strong need to further develop materials and methods for investigating the mechanistic behavior of these compounds and for treating diseased and other abnormal states associated with the physiological processes in which NPY and PYY act. Specifically, the NPY analogs/fragments that induce feeding, such as (LP)(3-36)NPY, do not bind to the previously identified NPY/PYY receptors with affinities consistent with the feeding response. Accordingly, there is a need and desire to identify the NPY/PYY receptor that is responsible for the feeding response. Antagonists to such a receptor could be used to treat obesity and diabetes by reducing appetite and food consumption.
The present invention provides, inter alia, novel NPY/PYY receptor proteins. Also provided are the nucleic acid sequences encoding these novel receptor proteins, as well is compounds and methods for using these proteins and their nucleic acid sequences.
The present invention provides novel proteins, nucleic acids, and methods useful for developing and identifying compounds for the treatment of such diseases and disorders as obesity. Identified and disclosed herein is the protein sequence for a novel receptor for the neurotransmitters Neuropeptide Y (NPY) and Peptide YY (PYY) and the nucleic acid sequence encoding this receptor, which we call the NPY Y5 (or simply xe2x80x9cY5xe2x80x9d) receptor. The importance of this discovery is manifested in the effects of NPY, which include blood pressure regulation, memory enhancement, anxiolysis/sedation, and increased food intake. Thus, this receptor protein is useful for screening for NPY/PYY agonist and antagonist activity for controlling these conditions.
In one aspect of the present invention, we provide isolated nucleic acid sequences for a novel NPY and PYY receptor, the Y5 receptor. In particular, we provide the cDNA sequences encoding for the rat and human receptors and isoforms thereof. These nucleic acid sequences have a variety of uses. For example, they are useful for making vectors and for transforming cells, both of which are ultimately useful for production of the Y5 receptor protein. They are also useful as scientific research tools for developing nucleic acid probes for determining receptor expression levels, e.g., to identify diseased or otherwise abnormal states. They are useful for developing analytical tools such as antisense oligonucleotides for selectively inhibiting expression of the receptor gene to determine physiological responses.
In another aspect of the present invention, we provide a homogenous composition comprising the receptor Y5 protein. The protein is useful for screening drugs for agonist and antagonist activity, and, therefore, for screening for drugs useful in regulating physiological responses associated with the Y5 receptor. Specifically, antagonists to the Y5 receptor could be used to treat obesity and diabetes by reducing appetite and food consumption, whereas agonists could be used for the treatment of anorexic conditions. The proteins are also useful for developing antibodies for detection of the protein.
Flowing from the foregoing are a number of other aspects of the invention, including (a) vectors, such as plasmids, comprising the receptor Y5 nucleic acid sequence that may further comprise additional regulatory elements, e.g., promoters, (b) transformed cells that express the Y5 receptor, (c) nucleic acid probes, (d) antisense oligonucleotides, (e) agonists, (f) antagonists, and (g) transgenic mammals. Further aspects of the invention comprise methods for making and using the foregoing compounds and compositions.
The foregoing merely summarizes certain aspects of the present invention and is not intended, nor should it be construed, to limit the invention in any manner. All patents and other publications recited herein are hereby incorporated by reference in their entirety.